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Aug. 18, 2010 -- A diet rich in omega-3 fish oil or healthy monounsaturated fats found in oils such as olive and canola may be beneficial for people with metabolic syndrome.

Metabolic syndrome is a cluster of risk factors known to increase risk for heart attack and diabetes. Features of metabolic syndrome include high blood pressure, insulin resistance, high cholesterol levels, and abdominal fat. The new findings appear in the September issue of the Journal of Nutrition.

In the study, 117 people with metabolic syndrome were placed on one of four special diets for 12 weeks:

A diet high in saturated fat

A diet high in monounsaturated fat

A diet low in fat and high in complex carbs such as whole grains, fruits, and vegetables

A low-fat diet high in complex carbs that was supplemented with omega-3 fatty acids

All of the diets contained similar amounts of calories.

Participants' blood was tested before and after a meal at the beginning and the end of the study. All the participants showed similar levels of blood cholesterol and blood fats called triglycerides before the study began. After the 12-week study period, however, people who ate diets rich in monounsaturated fat or low-fat, high complex carbs and omega-3 fatty acids had lower triglycerides than their counterparts who were placed on the other two diets.

Study participants whose diets were low in fat and high in complex carbs, a diet sometimes used for weight loss, displayed spikes in cholesterol and triglycerides after their meal. The addition of omega-3 fatty acids, such as found in fish oil, however, seemed to mitigate these effects, the study showed. Fish oil has been shown to reduce triglycerides and improve other cardiovascular risk factors.

Now, the researchers write, "it would be interesting to extend out studies beyond 12 weeks to confirm the longer-term effects of dietary fat interventions on cardiovascular risk factors in metabolic syndrome."